SA283 Grade C is a low-carbon structural steel plate with a minimum yield strength of 30,000 psi (205 MPa), offering a good balance of moderate strength and excellent weldability for general fabrication, storage tanks, and light structural components.
SA283 Grade B is a similar low-carbon structural steel plate but with slightly lower strength, featuring a minimum yield strength of 27,000 psi (185 MPa), making it a cost-effective choice for less demanding applications like covers, housings, and basic supports where maximum formability is prioritized.
The primary difference between SA283 Grade C and SA283 Grade B is their minimum yield strength, with Grade C being stronger. Both are low-carbon, general-purpose structural steel plates with excellent weldability and formability.
Here is a detailed comparison:
Key Difference: Strength
| Property | SA283 Grade B | SA283 Grade C |
|---|---|---|
| Minimum Yield Strength | 27,000 psi (185 MPa) | 30,000 psi (205 MPa) |
| Minimum Tensile Strength | 50,000 psi (345 MPa) | 55,000 psi (380 MPa) |
Result: Grade C is approximately 11% stronger in yield strength than Grade B. This allows Grade C to handle slightly higher loads or use slightly thinner sections for the same design load.
Supporting Difference: Chemical Composition
To achieve the higher strength, Grade C permits a slightly higher carbon content.
Grade B: Carbon max is typically 0.22%.
Grade C: Carbon max is typically 0.24%.
Practical Impact: This minor difference has negligible effect on weldability or formability for most fabrication. Both grades are considered highly weldable without mandatory preheat for common thicknesses.
Selection Guide: When to Use Which
Choose SA283 Grade B when:
The design requires only light to moderate strength.
Cost is the absolute driving factor (Grade B is often slightly cheaper).
For non-critical parts like covers, housings, or simple supports where maximum formability is desired.
Choose SA283 Grade C when:
You need a bit more strength for structural components, bins, or platforms.
You want a common, general-purpose "workhorse" plate that offers a good strength-to-cost balance.
For applications like ductwork, truck frames, or storage tanks where the slightly higher strength provides a useful margin.
Important Commonality
Both grades share these critical features:
No mandatory impact toughness (Charpy) requirements.
Not suitable for pressure-retaining parts (use SA516 for pressure vessels).
Excellent weldability and formability.
Summary:
SA283 Grade B and Grade C are part of a strength ladder. If your design calculations call for a minimum yield strength greater than 27 ksi, you must select Grade C (or higher). If 27 ksi is sufficient, Grade B is a viable, often more economical option. For most general fabrication where a specific grade isn't dictated, Grade C is the more commonly selected and stocked option due to its versatile strength level.
1. What Is SA283 Grade C?
SA283 Grade C is a low-carbon, general-purpose structural steel plate in the ASTM A283 standard, commonly used for low-stress structural applications like tanks, bins, and building frames where welding and forming are required.
2. What Is The Yield Strength Of SA283 Grade C?
The minimum yield strength of SA283 Grade C is 30,000 psi (205 MPa), making it suitable for applications with moderate structural loads.
3. What Is The Difference Between SA283 Grade A, B, C, And D?
The primary difference is increasing strength: Grade A (24 ksi min yield), Grade B (27 ksi), Grade C (30 ksi), and Grade D (33 ksi). Higher grades offer more strength but slightly less formability.
4. Is SA283 Grade C Weldable?
Yes, SA283 Grade C has excellent weldability due to its low carbon content, making it suitable for most common welding methods like SMAW, GMAW, and SAW without requiring complex procedures.
5. What Is SA283 Grade C Equivalent To In Europe?
The closest European equivalent is S235JR (EN 10025-2) based on comparable yield strength (~235 MPa nominal) and general application. Note that S235JR has mandatory impact toughness.
6. Where Is SA283 Grade C Commonly Used?
It is used in fabricating storage tanks, water towers, ductwork, building frames, agricultural equipment, and other general structural components not subjected to high stress or pressure.
7. Can SA283 Grade C Be Galvanized?
Yes, its low-carbon, low-alloy composition makes it an excellent candidate for hot-dip galvanizing, commonly used for outdoor structural components requiring corrosion protection.
8. What Is The Chemical Composition Of SA283 Grade C?
Typical composition includes Carbon (max 0.24%), Manganese (max 0.90%), Phosphorus (max 0.035%), and Sulfur (max 0.04%), ensuring good weldability and formability.
9. Is SA283 Grade C A Pressure Vessel Steel?
No, it is not rated for pressure-retaining service. For pressure vessels, materials like SA516 Grade 60 or 70 (with notch toughness requirements) are specifically designed and coded for that purpose.
10. What Is The Difference Between SA283 And A283?
There is no technical difference. A283 is the ASTM material standard, while SA283 is the ASME Boiler and Pressure Vessel Code adoption of the same standard, requiring ASME-compliant certification for code-bound components.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
